In recent years, a product has increased in number that adopts a solid-state light-emitting device such as a light-emitting diode (Light Emitting Diode; LED) and a laser diode (Laser Diode; LD) instead of a currently-available high-pressure mercury lamp, a xenon lamp, etc. for a light source in use for a projector, etc. for presentation or digital cinema. The solid-state light-emitting device such as the LED is more advantageous than a discharge lamp in terms of not only size and power consumption but also high reliability. In particular, to achieve further enhanced luminance and lowered power consumption, it is effective to improve the light use efficiency with use of the LD that serves as a point light source.
As a projector with use of the LD for a light source, a projector has been developed that utilizes fluorescent light generated in a manner of exciting a fluorescent body that is formed as a film on a rotating base using a laser beam emitted from the LD. In such a projector, it is necessary to suppress rise in temperature in consideration of temperature characteristics in the optical conversion efficiency of the fluorescent body, and thermal resistance of a binder, etc. for forming the fluorescent body on the base. Therefore, for example, PTL 1 discloses a projector that provides accommodation for a fluorescent wheel unit in which a fluorescent layer is formed, and a fluorescent wheel that is rotary-driven by a motor is attached, and a blower fan that blows cooling air to a light-emitting section of the fluorescent layer in a sealed container. The sealed container is provided with an air-circulating pathway in such a manner that the air from the blower fan flows through the light-emitting section of the fluorescent wheel.
Further, PTL 2 and PTL 3 propose a non-rotating method that performs heat dissipation of the fluorescent body with use of a heat sink without rotating the fluorescent wheel. For example, the PTL 2 proposes a structure in which a spacer and the fluorescent body are disposed on a substrate with the heat sink provided on a back surface thereof, and the spacer and the fluorescent body are bonded in a state of being interposed between the substrate and a light-collecting lens in a plano-convex shape that collects excitation light. Further, PTL 3 proposes a structure that seals the fluorescent body disposed on the substrate by a light-collecting lens in a meniscus shape.